The present invention relates to a variable reluctance type angle sensor.
A conventional variable reluctance type angle sensor is disclosed in, for example, Japanese Laid-Open Patent Publication No. 58-207850. The sensor includes a stator formed by winding an excitation coil and output coils of two phases (sine phase output coil and cosine phase output coil) around teeth arranged in the circumferential direction. Also, the sensor includes a rotor, which radially faces the teeth of the stator and has a shape such that the gap permeance with respect to the stator changes in a sinusoidal fashion in accordance with its rotational angle. The output winding of each phase is wound about the corresponding tooth by concentrated winding and forms the output coil. An induced voltage is generated in each output coil due to changes in the magnetic flux caused by rotation of the rotor. The total sum of the induced voltages of the output coils of each phase is obtained as the output voltage of the output winding of each phase. The rotational angle of the rotor can be detected based on the output voltage from the output winding of each phase, which changes in a sinusoidal fashion in accordance with rotation of the rotor.
However, three types of windings including the excitation coil and the output windings of two phases are required in the above-mentioned variable reluctance type angle sensor, and the structure of the sensor is complicated.